New 2,2'-bipyridine-chloroacetato complexes of transition metals(II)

Article abstract of DOI:10.1007/s10973-005-0843-y

The new mixed-ligand complexes of d-electron metals (M(II)=Mn, Ni, Cu) with 2,2'-bipyridine (2-bpy) and mono- or dichloroacetates were prepared as crystalline solids. The general formulae of the synthetized complexes are: Cu(2-bpy)₂(CClH₂COO)₂?2H₂O, Mn(2-bpy)₂(CCl₂HCOO)₂, M(2-bpy) ₂(CCl₂HCOO)₂?2H₂O (M(II)=Ni, Cu). The compounds were characterized by chemical analysis, IR and VIS spectroscopy. Their magnetic, molar conductivity and thermal properties also were studied. During heating in air complexes decompose via different intermediate products to metal oxides. A coupled TG-MS system was used to analyse the principal volatile thermal decomposition (or fragmentation) products of 2,2'-bipyridine-chloroacetato complexes.

Full text of DOI:10.1007/s10973-005-0843-y

Journal of Thermal Analysis and Calorimetry, Vol. 82 (2005) 69–75
NEW 2,2’-BIPYRIDINE–CHLOROACETATO COMPLEXES OF
TRANSITION METALS(II)
*
D. Czakis-Sulikowska and A. Czylkowska
Institute of General and Ecological Chemistry, Technical University, ˜ódü, Poland
The new mixed–ligand complexes of d–electron metals (M(II)=Mn, Ni, Cu) with 2,2’-bipyridine (2-bpy) and mono- or dichloroacetates
were prepared as crystalline solids. The general formulae of the synthetized complexes are: Cu(2-bpy)
2 2 2 2
(CClH COO) ·2H O,
Mn(2-bpy) (CCl HCOO) , M(2-bpy) (CCl HCOO) ·2H O (M(II)=Ni, Cu). The compounds were characterized by chemical analysis, IR
2
2
2
2
2
2
2
and VIS spectroscopy. Their magnetic, molar conductivity and thermal properties also were studied. During heating in air complexes de-
compose via different intermediate products to metal oxides. A coupled TG-MS system was used to analyse the principal volatile thermal
decomposition (or fragmentation) products of 2,2’-bipyridine–chloroacetato complexes.
Keywords: 2,2’-bipyridine–dichloroacetato complexes, 2,2’-bipyridine–monochloroacetato complexes, complexes of transition
metals(II), IR-VIS spectra, TG-MS data, thermal analysis
Introduction
Experimental
Preparation of complexes
Coordination compounds of transition metals with
2
,2’-bipyridine (2-bpy) are current interest for their
Mono- and dichloroacetates of metal(II) as hydrate
products were prepared by method described in the
literature [15, 16]; 2,2’-Bipyridine (m.p. 72°C) was
obtained from Aldrich; other chemicals were the same
as described in our previous papers [15, 16]. The
complexes were prepared by reacting cold water solu-
rich physico-chemical properties, reactivity patterns
and potential application in catalysis, analysis,
bioorganic systems and as new types of materials
[
1–7]. The 2,2’-bipyridine–carboxylate complexes of
metal ions have been extensively investigated during
many years [8–10]. However, there is scan informa-
tion on the mixed-ligand complexes of metal(II) with
tions of Cu(CClH
(
2
COO)
where M(II)=Mn, Ni, Cu) with 2,2’-bipyridine in
2
and M(CCl HCOO)
2 2
2
-bpy and chloroacetates [11]. In our earlier works
12–14] complexes formed between 2-bpy and
96% v/v ethanol. Over a period of several minutes
precipitates of complexes:
[
metal(II) trichloroacetates (M(II)=Mn, Co, Ni, Zn,
Cd), dichloroacetates (Zn, Cd) or monochloroacetates
Cu(2-bpy) (CClH COO) ·2H O
2
(1)
(2)
(3)
(4)
2
2
2
(
Mn) were prepared. We also obtained some metal(II)
complexes containing other isomers of bipyridine
4,4’- or 2,4’-bipyridine) and mono-, di- or
Mn(2-bpy) (CCl HCOO)
2
2
2
Ni(2-bpy) (CCl HCOO) ·2H O
2
(
2
2
2
trichloroacetates [15–17]. They have been character-
ized by IR and VIS spectra, thermal and other proper-
ties. The influence of chloroacetate anions and struc-
ture of N–donors on the formation of the compounds
in the process of thermal decomposition and of the
types metal–ligand bonds was examined. This work is
continuation of our studies. In the present paper we
describe the synthesis and properties of new
and
Cu(2-bpy) (CCl HCOO) ·2H O
2 2 2 2
were obtained. Final products were removed by filtra-
tion, washed with cool EtOH, Et O and EtOH mixture
2
(
reaction mixture containing Co(CClH COO) or
1:1) and dried at room temperature. In the case of the
2
2
Co(CCl HCOO) and 2-bpy, two liquid phases are
2
2
formed. After 2–3 days no homogeneous precipitate
were formed. The metal analyses in mineralized sam-
ples of obtained complexes were carried out by
complexometric method. The content of C, H, and N
were determined by elemental analysis with V O -as
2,2’-bipyridine–monochloroacetato complex of Cu(II)
and 2,2’-bipyridine–dichloroacetato compunds of
Mn(II), Ni(II) and Cu(II). They were studied by chemi-
cal and thermal analysis, IR and VIS spectra, magnetic
and molar conductivity measurements.
2
5
an oxidizing agent. The theoretical decomposition
was confirmed by analysis in limits 0.05/0.5%. These
analytical results are presented in Table 1.
*
Author for correspondence: dczakis@p.lodz.pl
1
388–6150/$ 20.00
Akadémiai Kiadó, Budapest, Hungary
Springer, Dordrecht, The Netherlands
©
2005 Akadémiai Kiadó, Budapest

CZAKIS-SULIKOWSKA, CZYLKOWSKA
Methods
ter at 21°C of obtained complexes are listed in Table 1.
The experimental magnetic moments (at room tempera-
ture) of complexes (1)–(3) are closed to the values ob-
served for the metal ions with octahedral
IR spectra of complexes were determined using FTIR
8501 Shimadzu spectrometer. The samples were pre-
pared as KBr discs. Electronic spectra were recorded
–
on a Specord M40 spectrometer (12000–26000 cm )
1
stereochemistry [22]. Only the m value for complex
eff
(
4) is 1.63 M.B; which is a little lower than observed
range for octahedral complexes of Cu(II)
cald.=1.73 M.B, observed in the range
.70–2.20 M.B). This suggests the possibility of at
best a very weak magnetic interaction between the
in Nujol mulls. The molar conductivities (L ) of the
M
–1
–
3
complexes were measured on 1.0·10 mol L solu-
tions in MeOH, DMF and DMSO at 25±0.05°C;
OK-102/1 conductivity meter equipped with an OK
(
m
eff
1
902 electrode. The magnetic measurements were car-
ried out at room temperature by Gouy’s method using
+
+
paramagnetic centres of Cu (which are practically
magnetical isolated in this complex) [23]. The molar
conductivity of all complexes in DMSO, (1)–(2) in
DMF and (2) in MeOH presented behaviour interme-
diate between non- and 1:1 electrolytes; complexes
Hg[Co(NCS) ] as a calibrant. The correction for the
4
diamagnetism of the consistent atoms was calculated
by the Pascal’s constants [18]. The X-ray diffracto-
grams were recorded using a D-5000 diffractometer
(
1), (3), (4) in MeOH and (3)–(4) in DMF are 1:1
electrolytes [24].
All obtained compounds have very similar IR
and CuK (Ni-filtered) radiation. The measurements
a
were made in the 2q=2q–80° range. Thermal decom-
position studies were carried out on a derivatograph
type Q-1500 over a temperature range of 20–1000°C,
spectra in solid state, only the absorption bands of wa-
ter are not observed in Mn(2-bpy) (CCl HCOO) . IR
–
1
2
2
2
at heating rate of 10 K min , in static air atmosphere.
The sample mass was 100 mg; a -Al O served as the
spectra of obtained complexes exhibit several absorp-
tion bands characteristic for 2-bpy and OCO groups.
The fundamental vibration modes of these ligands are
summarized in Table 2. The absorption bands were
identified in accordance with the literature [25, 26]. In
spectra of complexes the bands assigned as ring
2
3
reference. The solid thermal decomposition products
in different temperatures were identified using
derivatographic curves and were confirmed by re-
cording the IR spectra of sinters (prepared during
heating of samples of complexes up to definite tem-
perature from TG). In the sinters presence of anions
stretching modes: CC, CN, CCi.r.str. (A symmetry),
1
–
CN, CCstr. (B symmetry) and ring ‘breathing’ modes
1
Cl was also investigated. The final solid products of
are observed in the range 1606.6–1598.9,
1
decomposition were verified by X-ray diffraction pat-
terns registration. Obtained X-ray diffractometric re-
sults were analyzed using the Powder Diffraction File
–
578.0–1566.1 cm and 1024.1–1014.5 cm , respec-
1
–1
tively. They are shifted to higher frequencies in com-
parison to free ligand. The characteristic aromatic
out-of-plane hydrogen deformation modes in
[
19]. TG-MS system was used to analyse the principal
volatile products formed during thermal decomposi-
tion (or degradation) process of complexes [20, 21].
TG-MS system, consisting of derivatograph
TG/DTA-SETSYS-16/18, coupled to a mass spectro-
meter (QMS-422), model ThermoStar Balzers Instru-
ments; dynamic measurements were carried out in air
–
1
unbonded 2-bpy are observed at 753 and 738 cm
satellite). The complexes exhibit very strong absorp-
(
–
1
tion in the range 779.2–757.6 cm ; the satellite of
this band gains intensity and is clearly splitted. Thus,
the obtained complexes are 2,2’-bipyridine chelate
compounds [27].
–
1
atmosphere, with flow rate of 1 L h between
0–1000°C. The samples were heated in platinum
The asymmetric nas(OCO) bands of carboxylate
group in complexes lie between 1684.3–1637.5 cm .
2
–
1
–
1
crucible 100 mL at heating rate 10°C min . Sample of
masses in the range ca 8–11 mg. An ion source tem-
perature of ca 150°C by using 70 eV electron impact
ionization.
The bands of symmetric vibrations n (OCO) for
s
–
complexes appear in the range 1420.0–1340.4 cm .
1
The n (OCO) are shifted to higher frequencies;
as
ns(OCO)– to the smaller values, compared to the
bands
of
sodium
salts.
The
separation
Results and discussion
Dn=n (OCO)–n (OCO) of these bands varies
as
s
–
1
between 319.3–234.8 cm and is in all cases, higher
than the Dn of corresponding sodium salts (Table 2).
It is reasonable to suggest that in obtained complexes
the therminal carboxylate groups exist [28–31]. In
Mixed-ligand complexes
Cu(2-bpy) (CClH COO) ·2H O
2
2
2
2
Mn(2-bpy) (CCl HCOO) ,
2
2
2
M(2-bpy) (CCl HCOO) ·2H O (M(II)=Ni, Cu)
2
these complexes showed a few bands of n (OCO) and
2
2
2
as
were prepared as crystalline solids. The analysis of
the diffractograms proved that obtained compounds
are small crystalline and non-isostructural. Magnetic
moments, molar conductivity data and solubility in wa-
ns(OCO), as well as, in several mixed metal(II)
complexes with N-donors and carboxylates [16,
32, 33]. This would seen to indicate that the
70
J. Therm. Anal. Cal., 82, 2005

NEW 2,2’-BIPYRIDINE–CHLOROACETATO COMPLEXES
o
Table 1 Analytical data: solubility (S) in water at 21 C, molar conductivity (L
M
) in MeOH, DMF and DMSO
–
3
–1
o
(
c=1·10 mol L ) and effective magnetic moments (meff) at 25 C
Complex Analysis: found (calculated)/%
colour)
(CClH COO)
blue)
Mn(2-bpy) (CCl
yellow)
(CCl HCOO)
green)
(CCl HCOO)
blue)
2
S 10 /
–1
2
–1
No.
L
M
/W cm mol
eff
m /
–1
(
M
C
N
H
mol L
MeOH DMF DMSO
M.B
1.88
(1)
(2)
(3)
(4)
Cu(2-bpy)
2
2
2
·2H
2
O
10.61
48.13
9.08
4.04
¨
83.3
74.7
31.6
46.0
65.2
63.6
28.7
48.1
47.5
33.3
(
(10.42) (48.08) (9.05) (4.01)
8.82 46.26 8.99 3.23
(8.86) (46.19) (9.04) (3.20)
8.86 43.48 8.58 3.65
(9.01) (43.51) (8.45) (3.61)
9.51 43.17 8.00 3.62
(9.13) (43.09) (8.39) (3.59)
2
2
HCOO)
2
0.1
6.08
3.08
1.63
(
Ni(2-bpy)
2
2
2
·2H
2
O
¨
¨
114.6
80.8
(
Cu(2-bpy)
2
2
2 2
·2H O
(
¨
– very right soluble
–
Table 2 Principal IR bands (cm ) for 2-bpy and OCO group in obtained complexes
1
Complex
Assignment
2-bpy [23]
(
1)
Coordination 2-bpy modes
606.6sh
598.5
(2)
(3)
(4)
1
1604.7sh
1598.9
n
1
2
1579
1595.8
1600.0
1
1
1
575.7
566.1
1575.7
1566.1
n
n
n
1553
991
1566.1
1012.6
1578.0
1015.5
3
4
1014.5
1024.1
7
7
53
38sh
769.5
731.0
771.5
738.7
757.6
736.8
779.2
732.9
Coordination carboxylate modes
NaCClH COO
NaCCl HCOO) [24]
2
(
2
1
603
1640)
1654.8
1666.4
1640.0
1668.3
1637.5
1684.3
1640.3
n
n
as(OCO)
(
(
1418
1399)
1420.0
1382.9
1350.1
1340.4
1365.0
s
(OCO)
pd
}
1355.9
185
241)
283.5
289.9
327.9
297.1
319.3
284.4
Dn=nas(OCO)-n
s
(OCO)
234.8
(
4
5
39.7
92.1
n(M–O) + d(OCO)
624.9
437.8
588.2
3
complexes have a cis–configuration [32] or forms
non-equivalent bonds between metal(II) and carboxy-
late ligands [34–36]. In the IR spectra of complexes
and T (P) transitions in O symmetry [37] are ob-
1g h
–1
served in complex (3) at ca 17700 and 26700 cm
(with a shoulder at 13300 cm ). The shoulder at ca
13300–13400 cm was observed in several comp-
lexes of Ni(II) with pyridine and halogenoacetates
[32]. The copper(II) complexes exhibit one asymmet-
ric band in the visible spectrum (broad maximum at
13000–14000 cm ), associated with three transitions
2
lying within one broad envelope: E , B2g and A1g
g
[38]. The position of these bands indicates probably a
pseudooctahedral environment around Cu(II).
–1
–
1
(
1), (3), (4) there are broad absorption bands with
–
1
maximum at ca 3400 cm , confirming the presence of
water molecules in the compounds.
The ligand–field spectra of Ni(II) complexes are
typical for six–coordination Ni(II) in pseudooctahedral
environment. This complex has magnetic and spectral
behaviours with octahedral geometry consistent. Three
–
1
2
2
1
3
spin–allowed bands corresponding to the E
, T1g(F)
g
J. Therm. Anal. Cal., 82, 2005
71

CZAKIS-SULIKOWSKA, CZYLKOWSKA
Thermal behaviour of complexes
between 60–85°C; the complexes of Cu(II) lose water
molecules in one step, whereas the complex (3) in two
steps. The thermal curves exhibit clearly defined dehy-
dration processes. The dehydration processes of com-
plexes are connected with endothermic effects. The an-
hydrous compounds decompose in very similar way. On
increase of the temperature, decomposition of the
chloroacetates ligand takes place, and the stepwise libera-
tion of 2-bpy begins. During these processes, intermediate
The obtained complexes are stable in air at room tem-
perature. Thermal decomposition of the compounds is a
multi–stage process. The TG, DTG and DTA curves for
Cu(II) complexes are shown in Figs 1 and 2. The ther-
mal data obtained from thermal curves, supported by
other investigation (see experimental) are collected in
Table 3. The hydrated complexes begin to lose water
species of the type M(2-bpy)2–xCl probably are formed. In
2
the sinters of complexes heated up to definite temperature
from TG (Table 3), only absorption bands for 2-bpy and
chlorine ions were evident. In the temperature range
2
75–700°C, during decomposition of Mn(2-bpy)1.5Cl
,
2
Mn O is formed (Fig. 3a). Above 900°C only diffrac-
2
3
tion lines characteristic of Mn O were detected (Fig.
3
4
3b). Anhydrate complex Ni(2-bpy) (CCl HCOO) lost
2 2 2
2-bpy in two steps, and intermediate products with for-
mulae Ni(2-bpy) Cl , Ni(2-bpy)Cl are formed. Next,
2
2
2
process of decomposition Ni(2-bpy)Cl takes place. A
2
plateau for pure NiO in the TG curve being obtained at
740°C. In case of the copper(II) complexes, total de-
composition of organic ligands is connected with the
formation and volatilization of Cu Cl and only 4.5–5%
x
x
CuO is formed as a final product. The existence of pure
MnCl and NiCl as intermediate solid products, was not
2
2
proved from TG and DTG curves and analytical data.
DTA curves of these complexes in the presence of air
may be a mixture of both endo and exo peaks (Table 3).
2 2 2
Fig. 1 TG, DTG, DTA curves of a – Mn(2-bpy) (CClH COO) ;
b – Ni(2-bpy) (CCl HCOO) ·2H O;
2
2
2
2
–1
sample mass 100 mg, heating rate: 10° min
Fig. 2 TG, DTG, DTA curves of
Fig. 3 X-ray diffraction patterns of decomposition of complex
Mn(2-bpy) (CCl HCOO) a – sintered at 720°C;
b – sintered at 920°C
a – Cu(2-bpy)
b – Cu(2-bpy)
sample mass 100 mg, heating rate: 10° min
2
(CClH
2
COO)
2
·2H
2
O;
(CCl HCOO)
2
2
·2H
2
O;
2
2
2
2
–
1
72
J. Therm. Anal. Cal., 82, 2005

NEW 2,2’-BIPYRIDINE–CHLOROACETATO COMPLEXES
–
Table 3 Thermal decomposition data, sample 100 mg; heating rate of 10°C min in air
1
Starting, intermediate and final products
Temperature range/°C
Temperature peak of DTA/°C
Mass loss/%
found. cald.
2 2 2 2
(1) Cu(2-bpy) (CClH COO) ·2H O
¯
60- 100
120- 300
300- 370
370- 700
100 endo
195 exo, 200 endo
335 endo
5.5
46.0
13.0
34.0
6.02
45.45
13.04
22.21
Cu(2-bpy)
2
(CClH
2
COO)
2
¯
Cu(2-bpy)Cl
2
¯
Cu(2-bpy)0.5Cl
a
2
¯
400, 600 exo
CuO
(2) Mn(2-bpy)
2
(CCl
2
HCOO)
2
¯
165- 275
275- 700
>900
220 exo
465, 540, 630, 680 exo
760 exo
43.0
44.0
~1.0
42.21
45.12
0.43
Mn(2-bpy)1.5Cl
2
¯
Mn
2
O
3
4
¯
Mn
3
O
(3) Ni(2-bpy)
2
(CCl
2
HCOO)
2
2
·2H O
¯
60- 100
100- 138
138- 260
260- 405
405- 740
80 endo
120 endo
2.7
3.0
2.72
2.72
Ni(2-bpy)
2
2
2
(CCl
(CCl
2
2
HCOO)
2
2
2
·H O
¯
Ni(2-bpy)
¯
HCOO)
220 exo
28.3
24.0
32.5
27.89
23.56
31.84
Ni(2-bpy)
b
¯
Cl
2
320 endo
Ni(2-bpy)Cl
b
¯
2
460, 620 exo, 500 endo,
NiO
2 2 2 2
(4) Cu(2-bpy) (CCl HCOO) ·2H O
¯
85–145
145- 258
258- 375
375–700
130 endo
190 exo, 240 endo
330 endo
5.0
40.0
17.5
34.0
5.40
2 2 2
Cu(2-bpy) (CCl HCOO)
¯
39.39
17.54
25.76
Cu(2-bpy)1.5Cl
2
¯
Cu(2-bpy)0.75Cl
2
a
¯
400, 600 exo
~4,5% CuO
a
b
take place; probably via Ni(2-bpy)2-xCl
total decomposition of organic ligands and probably gradual volatilization of Cu
x
Cl
x
2
,
o
TG curve shows bending at 340 and 500 C
o
The endothermic effects are due to decomposition of in-
termediate complexes and chloroacetate ligands and
exothermic to the ligand combustion. The very strong
and broad exothermic maxima with centers at: 400° (1),
465, 540° (2), 460° (3) and 400°C (4) were observed on
the DTA curves.
Thermogravimetry coupled with mass spectros-
copy (TG-MS) was used to characterize only complexes
J. Therm. Anal. Cal., 82, 2005
73

CZAKIS-SULIKOWSKA, CZYLKOWSKA
((2)–(4)) containing 2-bpy and dichloroacetate ligands.
The mass spectra of all these complexes present the sim-
ilar signals. The principal ion current may indicate for:
+
H , C , OH , H O , CN (or C H ), CHO , NO (or
+
+
+
+
+
+
+
2
2
2
· +
+
+
+
+
2
+
2
CH O ), Cl , HCl , Cl , CO , bpy (m/z=1, 12, 17, 18,
2
27, 29, 30, 35, 36, 70, 44, 78), additionally m/z=50, 76
and 84 and traces of other. Figure 4 (as an example)
presents the chemogram for selected profiles of ion cur-
rent of Ni(2-bpy)
are observed at ca: 200–209, 450–460, 700°C (2), 150,
10–220, 465°C (3), 190, 340–360 and 550°C (4). The
characteristic MS peaks for crystalline water appeared at
38°C for (3) and at 150°C for (4). The absence of
m/z=18–signal to elimination of H O crystalline for (2)
2 2 2 2
(CCl HCOO) ·2H O. Many signals
2
1
2
is stated. Maximum rates of forming H O during de-
2
composition of organic ligands at: 456, 629, 689° (2),
467° (3) and 358°C (4) are observed. The ion signals in-
+
tensities of CO2 have centres at: 188, 270, 428, 447,
33° (2), 208, 466, 561° (3), 196, 362 and 547°C for (4).
5
The species containing halogen (Cl , HCl , Cl , CCl ,
+
+
+
+
2
+
CClH , CCl H and m/z=50) have several centres on
+
2
2
chemograms with maximum at: 182–225°, 196–228°,
92–276°, 188–466° and 176–269°C, respectively. Cor-
relation of MS data with the mass loss in the TG curves
1
and IR measurements (for sinters), shows that in the first
+
O are released; fol-
lowed the decomposition of dichloroacetate ligands
step the molecules of crystalline H
2
+
takes place. Maximum rates of forming NO (or CH O )
+
Fig. 5 TG curve and ion current detected by the MS in air for
Cu(2-bpy) (CCl HCOO) ·2H O mass sample 8.02 mg
2
2
2
2
2
at: 456, 545° for (2), 474, 561° for (3) and 565°C for
>
+
a – m/z: 1–44; 2–50; 3–70 with sensitivities of: E-09,
E-12, E-12 A, respectively; b – m/z: 1–18; 2–30; 3–35
with sensitivities of: E-09, E-10, E-11 A, respectively
complex (4) are observed. In case of m/z=76 and bpy
were detected very low intensities with several peaks
(
(
majority at ca: 682, 700° (2), 465° (3) and 360, 670°
4). Nitrogen–containing ions observed by MS coincide
with decomposition of intermediate products of the type
M(2-bpy)2–xCl . TG-MS curves for selected ions current
are presented, as an example, in Fig. 5.
2
Conclusions
New mixed-ligand complexes of general formulae:
Cu(2-bpy) (CClH COO) ·2H O,
Mn(2-bpy) (CCl HCOO) ,
2
2
2
2
2
2
2
M(2-bpy) (CCl HCOO) ·2H O (M(II)=Ni, Cu) were
2
2
2
2
prepared. The influence of nitrogen atom position in
the bipyridine causes changes in the composition of
the mixed-complexes with halogenoacetates. Ob-
tained in this work complexes have analogous molar
ratio of metal(II) to organic ligands 1:2:2 as com-
plexes of the types: M(2-bpy) (CCl COO) ·nH O and
2
3
2
2
M(2,4’-bpy) (CCl HCOO) ·nH O [13]. The coordi-
2
2
2
2
nation compounds with 4,4’-bipyridine (4-bpy) have
the general formulae M(4-bpy)(hac) ·nH O, without
2
2
complexes of Ni(II) [13, 16], (where: hac=mono-, di-
or trichloroacetate) [13, 15, 16]. The IR data show
that 2-bpy coordinated in obtained complexes as
bidentate–chelating ligand. Carboxylate groups in
these compounds are bonded as monodentate. The
Fig. 4 The principal ion current detected in the mass
spectrometer vs. time, in air, for complex
Ni(2-bpy)
2
(CCl
2
HCOO)
2
×2 H
2
O; heating rate
–
1
0 K min ; mass sample 11.07 mg, m/z: 1–1; 2–12;
1
3
1
–17; 4–18; 5–27; 6–29; 7–30; 8–35; 9–36; 10–44;
1–50; 12–70; 13–76; 14–78
isolated complexes M(2-bpy) (CCl HCOO) ·2H O
2 2 2 2
74
J. Therm. Anal. Cal., 82, 2005

NEW 2,2’-BIPYRIDINE–CHLOROACETATO COMPLEXES
(M(II)=Ni, Cu) are ligand–isomeric with the 2,4’-bi-
pyridine complexes [13].
The stability of the hydrate compounds synthe-
sized in this work is very similar. They begin to lose
water at 60–85°C. The anhydrated complexes con-
taining dichloroacetate ligands are thermally more
14 A. Czylkowska, R. KruszyÕski, D. Czakis-Sulikowska and
T. J. Bartczak, J. Coord. Chem., 57 (2004) 239.
5 D. Czakis-Sulikowska, A. Czylkowska and
J. RadwaÕska-Doczekalska, J. Therm. Anal. Cal.,
1
1
63 (2001) 387.
6 D. Czakis-Sulikowska, A. Czylkowska and
A. Malinowska, ibid. 65 (2001) 505; ibid. 67 (2002) 667.
stable; Mn(2-bpy) (CCl HCOO) has the highest sta-
2
2
2
17 D. Czakis-Sulikowska and A. Malinowska, Polish
J. Chem., 76 (2002) 1047.
bility (165°C). After dehydration of mono- and
dichloroacetates takes place. The intermediate prod-
ucts of M(2-bpy)2–xCl are formed. The species of the
18 R. Weller and W. E. Hatfield, J. Chem. Ed.,
56 (1978) 652.
2
1
2
2
2
9 Powder Dffraction File. International Center of Diffraction
Date. ICPDS-ICBD, 1990. Park Lane Swarthmore.
0 B. PtaszyÕski and A. ZwoliÕska, J. Therm. Anal. Cal.,
types M(bpy)2–xCl (where: bpy=2-bpy; 4-bpy and
2
2
,4’-bpy) also occurs during pyrolysis of 2,2’-bi-
pyridine–trichloroacetato, 2,4’-bipyridine (or 4,4’-bi-
pyridine)–dichloroacetato complexes of metal(II)
7
4 (2003) 237.
1 B. PtaszyÕski and A. ZwoliÕska, J. Therm. Anal. Cal.,
5 (2004) 301.
[
13]. The resultant final products were the Mn O and
3 4
7
NiO, respectively. These conclusions are in agree-
ment in the literature on other metal carboxylate com-
plexes [39–40]. During decomposition of Cu(II) com-
plexes, the volatile Cu Cl are formed and only trace
2 F. E. Mobbs and D. J. Machin, Magnetism and Transition
Metal Complexes; Chapman O. Hall, London 1973.
23 M. Hvastijová, J. Kohout, M. Okruhlica and J. MroziÕski,
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4 W. J. Geary, Coord. Chem. Rev., 7 (1971) 81.
5 J. S. Strukl and J. L. Walter, Spectrochim. Acta,
x
x
2
2
of CuO was observed as residue solid product. The
volatile species produced during pyrolysis (or frag-
mentation) of metal(II) complexes with bipyridine
isomers (2-bpy, 4-bpy and 2,4’-bpy) and dichloro-
acetates are similar, only major maxima of ions
current are shifted.
2717 (1971) 299.
2
2
2
6 E. Spinner, J. Chem. Soc., (1964) 4217.
7 S. P. Sinha, Spectrochim. Acta, 20 (1962) 879.
8 B. S. Manhas and A. K. Trikha, J. Indian Chem. Soc.,
LIX (1982) 315.
2
9 K. Nakamoto, Infrared and Raman Spectra of Inorganic
and Coordination Compounds, John Wiley and Sons, New
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J. Therm. Anal. Cal., 82, 2005
75